We give two proofs of this theorem. After reviewing some background in Section 2, we begin Section 3 by proving two preliminary lemmas that square up several definitions introduced by Durham–Fanoni–Vlamis and Mann–Rafi. Theorem REF  then follows directly from a strictly stronger result of Mann–Rafi [1]}. Our second proof of Theorem REF  is given in Section 4. This proof uses the same preliminary lemmas but then follows the style of the arguments of Durham–Fanoni–Vlamis.
